NHTSA said on Wednesday it was launching an investigation into the Dec. 29 crash of a Tesla Model 3 that left a passenger dead after the vehicle collided with a parked fire truck in Indiana.
The crash is the 14th involving Tesla that NHTSA's special crash investigation program has taken up in which it suspects the company's so-called Autopilot or other advanced driver assistance system was in use.
It is the third Tesla crash NHTSA has said it was investigating in recent weeks. Autopilot had been engaged in at least three Tesla vehicles that were involved in fatal U.S. crashes since 2016. Tesla did not immediately comment.
NHTSA is also probing another Dec. 29 fatal crash of a Model S Tesla in Gardena, Calif. In that incident, the vehicle exited the 91 Freeway, ran a red light and struck a 2006 Honda Civic, killing its two occupants.
Also in December, NHTSA had said it was investigating a crash in which a Tesla Model 3 rear-ended a parked police car in Connecticut.
The crashes raised questions about the driver-assistance system’s ability to detect hazards, especially stationary objects. There are mounting safety concerns about systems that can perform driving tasks for extended stretches of time with little or no human intervention, but which cannot completely replace human drivers.
The NTSB has criticized Autopilot's lack of safeguards and said in September in its probe of a 2018 Culver City, Calif., Tesla crash that the system’s design "permitted the driver to disengage from the driving task."
Tesla and NHTSA both advise drivers that they must keep their hands on the steering wheel and pay attention at all times while using Autopilot. Tesla says Autopilot "enables your car to steer, accelerate and brake automatically within its lane," but does not make the vehicle autonomous.
Some drivers say they are able to keep their hands off the wheel for extended periods when using the system. In November, U.S. Sen. Ed Markey said Tesla should disable Autopilot until it installs new safeguards to prevent drivers from evading system limits that could let them fall asleep.
NHTSA said its special crash investigation team has reviewed a total of 23 crashes involving vehicles where it was believed some form of advanced driver assistance system played a role.
